It is known in the art to provide a device on the front of the machine body, above or below the guide bar, for engagement against the object to be worked by means of the machine, which device shall be able to form a centre of rotation for a turning of the machine for the purpose of augmenting the power pressure of the guide bar and hence of the saw chain against the bottom of the kerf which the saw chain is establishing in the object. In its most elementary design, a dog device of that type according to the prior art consists of a pointed, projecting metal spike on the machine body on a level immediately below or immediately above the guide bar. Also more complicated devices are employed, including a system of parallel links in which affront spike which, when engaging the front side of the object which is being worked, presses the guide bar downwards by means of a spring force, such that the machine need not be turned to achieve an augmentation of the power pressure. The device has evident advantages in theory, but in practice it has substantial deficiencies, mainly because of its design which is easily damaged, and which is difficult to make stronger unless the design is made much more robust and hence also heavier, more cumbersome and more expensive.